Backup and Restore of File System Objects of Unknown Type

1. A computer-implemented method comprising: receiving a list of file system objects from a first file system, the file system objects to be backed up by a backup application, the backup application running in relation to a second file system different than the first file system, each file system object having a file type that is known to the first file system where the file type of at least one file system object is unknown to the second file system; for each file system object of the list of file system objects, determining whether the file type of the file system object is known or unknown to the second file system; in response to determining that the file type of the file system object is unknown, performing: querying the first file system to obtain information regarding the file system object for the first file system to later recreate the file system object; and, storing, by the backup application, the file system object and the information regarding the file system object in the second file system; and, in response to determining that the file type of the file system object is known, storing, by the backup application, the file system object at the second file system, wherein the first file system is queried to obtain the information only with respect to each file system object having an unknown file type, and the first file system is not queried to obtain the information with respect to each file system object having a known file type.

2. The method of claim 1 , wherein the list of file system objects is received by the backup application, and the backup application queries the first file system to obtain the information regarding the file system object for the first file system to later recreate the file system object.

3. The method of claim 1 , further comprising querying the first file system for the list of file system objects to be backed up from the first file system.

4. The method of claim 1 , wherein determining whether the file type of the file system object is known or unknown comprises calling a component of the first file system to determine whether the file type is known or unknown.

5. The method of claim 1 , further comprising receiving from the first file system the information regarding the file system object for the first file system to later recreate the file system object.

6. The method of claim 1 , wherein querying the first file system to obtain the information regarding the file system object for the first file system to later recreate the file system object comprises calling an interface to obtain the information regarding the file system object to recreate the file system object upon subsequently being provided back to the first file system.

7. The method of claim 6 , further comprising installing a library specific to the file system, the library exposing the interface.

8. The method of claim 1 , wherein querying the first file system to obtain the information regarding the file system object for the first file system to recreate the file system object comprises querying the first file system to obtain a binary large object (BLOB) attribute of the file system object for the first file system to later recreate the file system object.

9. The method of claim 8 , wherein storing the file system object and the information regarding the file system object comprises storing the file system object and the BLOB attribute of the file system object.

10. The method of claim 1 , wherein each of the file system objects that has a file type unknown to the backup application is a file type selected from: a symbolic link, a named pipe, and a device special file.

11. A computer-implemented method comprising: retrieving a file system object to be restored to a first file system; determining whether a file type of the file system object is known or unknown to a second file system in relation to which a backup application is running, the file type known to the first file system; in response to determining that the file type of the file system object is unknown, retrieving information regarding the file system object, as previously provided by the first file system and as previously stored at the second file system, the information regarding the file system object for the first file system to recreate the file system object, where the file system object and the information regarding the file system object are both previously stored by the backup application; sending the file system object and the information regarding the file system object to the first file system to recreate the file system object at the file first system; and, in response to determining that the file type of the file system object is known, sending the file system object to the first file system to recreate the file system object at the first file system, wherein the information is retrieved only where the file system object has an unknown file type, and the information is not retrieved where the file system object has a known file type, wherein the file system object is one of a plurality of file system objects that have been backed up to the second file system, each file system object having a file type that is known to the first file system the file type of at least one of the file system objects being unknown to the second file system.

12. The method of claim 11 , wherein the backup application retrieves the file system object to be restored to the first file system, the backup application retrieves the information regarding the file system object as previously provided by the file system object, and the backup application sends the file system object and the information regarding the file system object to the first file system.

13. The method of claim 11 , further comprising repeating the method for each of at least one additional file system object to be restored to the first file system, as previously backed up from the first file system.

14. The method of claim 11 , wherein determining whether the file type of the file system object is known or unknown comprises, where the file system object has the information regarding the file system object for the first file system to recreate the file system object stored with the file system object, concluding that the file type is unknown.

15. The method of claim 11 , wherein sending the file system object and the information regarding the file system object to the first file system to recreate the file system object at the file system comprises calling an interface to submit the file system object and the information regarding the file system object to recreate the file system object using the information regarding the file system object.

16. The method of claim 11 , wherein the information regarding the file system object comprises a binary large object (BLOB) attribute of the file system object for the first file system to recreate the file system object.

17. The method of claim 11 , wherein the file system object that has a file type that is unknown is a file type selected from: a symbolic link, a named pipe, and a device special file.

18. A computerized system comprising: hardware comprising a processor; a first file system storing a plurality of file system objects; a second file system to backup the file system objects, each file system object having a file type that is known to the first file system, where the file type of at least one file system object is unknown to the second file system; and, an application implemented by the hardware to backup the file system objects from the first file system to the second file system, wherein the application is to, for each file system object of the list of file system objects, determine whether a file type of the file system object is known or unknown to the second file system; in response to determining that the file type of the file system object is unknown, performing: query the first file system to obtain information regarding the file system object for the first file system to later recreate the file system object; and, store the file system object and the information regarding the file system object; and, in response to determining that the file type of the file system object is known, store the file system object, wherein the first file system is queried to obtain the information only with respect to each file system object having an unknown file type, and the file system is not queried to obtain the information with respect to each file system object having a known file type.

19. The computerized system of claim 18 , wherein the application is a backup application.

20. The computerized system of claim 18 , wherein the application has an interface to provide the information to the application regarding a file system object having a file type unknown to the application, in response to the application calling the interface as to the file system object.

21. The computerized system of claim 20 , wherein the interface is preinstalled by the application.

22. The computerized system of claim 18 , wherein the application is further to restore the file system objects as have been backed up back to the first file system, such that for each file system object having a file type unknown to the application, the application retrieves the information previously stored that is for the first file system to recreate the file system object.

23. The computerized system of claim 22 , wherein the first file system has an interface to recreate a file system object having a file type unknown to the application, in response to the application calling the interface as to the file system object and the information regarding the file system object that is for the first file system to recreate the file system object.

24. An article of manufacture comprising: a tangible computer-readable recordable data storage medium; and, means in the medium for backing up a plurality of file system objects from a first file system to a second file system, at least one of the file system objects of the file system having a file type that is unknown to the second file system, the file type of each file system object being known to the first file system, wherein the means is further for, for each file system object of the list of file system objects, determining whether a file type of the file system object is known or unknown; in response to determining that the file type of the file system object is unknown, performing: querying the first file system to obtain information regarding the file system object for the file system to later recreate the file system object; and, storing the file system object and the information regarding the file system object at the second file system; and, in response to determining that the file type of the file system object is known, storing the file system object at the second file system, wherein the first file system is queried to obtain the information only with respect to each file system object having an unknown file type, and the first file system is not queried to obtain the information with respect to each file system object having a known file type.

25. The article of manufacture of claim 24 , wherein the means is further for restoring the file system objects as have been backed up back to the file system, such that for each file system object having an unknown file type, the means retrieves the information previously stored that is for the first file system to recreate the file system object.